554 5.7.1 Unknown Sender in Local Domain

When sending an email from one server to another, the email gets bounced with an error

SMTP error from remote mail server after MAIL FROM:<root@forum.serverok.in> SIZE=1575: 554 5.7.1 Unknown Sender in Local Domain .

1	SMTP error from remote mail server after MAIL FROM:<root@forum.serverok.in> SIZE=1575: 554 5.7.1 Unknown Sender in Local Domain .

The error is because both servers have the sender domain name configured. The solution is to remove the domain name from one of the servers.